| CoID | Company | Type | Status | States Served | 24X7 Phone |
| CAV | Cavalier Telephone | CLEC Facility | A | DE | DC | MD | NJ | PA | VA | 800-200-1989 option 3 |
| CAVAL | Fort Baker Retreat Group - CANCELLED | 9-1-1 Admin-CPE ALI (9-1-1 Jurisdiction/PSAP ONLY) | C | CA | 415-686-9787 |
| CB101 | Code Blue Corporation | PBX/PS911/Shared Tenant VoIP Provider | A | USA - Nationwide | 616-636-7035 |
| CBAD | Cincinnati Bell Any Distance - CANCELLED | CLEC Facility | CLEC Reseller | CLEC UNE | C | USA | 513-397-7326 |
| CBC | Comcast Business Communications Inc. - CANCELLED | CLEC Facility | C | MA | PA | DE | NJ | 800-839-6707 |
| CBCBH | CBC Broadband Holdings, LLC(Inactive) | Cable Digital, CLEC Facility, VoIP Provider | C | CA | 323-908-1317 |
| CBCWA | Columbia Basin College | 9-1-1 Admin-CPE ALI (9-1-1 Jurisdiction/PSAP ONLY) | A | WA | 509-542-4777 |
| CBI | Constellation Brands Inc. | PBX/PS911/Shared Tenant | A | UT | 585-364-4002 |
| CBIT | CBIT Inc. | VoIP Provider | A | WA | 509-578-5424 |
| CBKS | US Army War College | PBX/PS911/Shared Tenant | A | PA | 717-245-3131 |
| CBL | Cooper B-Line - CANCELLED | ILEC | C | IL | 618-407-8297 |
| CBM | CBM Technology - CANCELLED | VoIP Reseller | C | LA | 337-233-5010 |
| CBS | CBS Corp(Inactive) | PBX/PS911/Shared Tenant | C | NY | 212-975-2811 |
| CBT | Cebridge Telecom (Cancelled) | Cable Digital, VoIP | C | TX,CA,LA,MO,OK,VA,WV,NC | 903-939-9008 |
| CBTC | Corn Belt Telephone | ILEC | A | IA | 712-664-2221 |
| CBTS | CBTS Technology Solutions | VoIP Reseller VoIP Provider | | USA - Nationwide | 888-783-2506 |
| CBURY | Canterbury School | PBX/PS911/Shared Tenant | A | CT | 860-210-3800 |
| CBW | Cincinnati Bell Wireless - CANCELLED | Wireless/Celluar/PCS | C | OH | IN | KY | 513-566-3100 |
| CBYND | Cbeyond Communications | CLEC UNE | A | GA | TX | CO | IL | CA | MI | MN | 866-424-9233 |
| CC52 | Coleman County Telephone Cooperative | Co-Op/Rural | A | TX | 325-348-3124 |
| CC715 | Sutter Health | 9-1-1 Admin-CPE ALI (9-1-1 Jurisdiction/PSAP ONLY) | A | USA - Nationwide | CA | UT | 916-363-2233 |
| CC911 | Colorado College | PBX/PS911/Shared Tenant | A | CO | 719-389-6707 |
| CCAIN | Clarity Communications Advisors | VoIP Provider | A | USA - Nationwide | 248-327-4309 |
| CCART | Cornish College of the Arts | PBX/PS911/Shared Tenant | A | WA | 206-726-5092 |
| CCAS | Cross Country Automotive Services - CANCELLED | PBX | C | ALL | 800-824-6678 |
| CCBC | The Community College of Baltimore County | 9-1-1 Admin-CPE ALI (9-1-1 Jurisdiction/PSAP ONLY) | A | MD | 443-840-1111 |
| CCBCP | Community College of Beaver County | PBX/PS911/Shared Tenant | A | PA | 724-480-3555 |
| CCBL | Cross Cable Television LLC | CLEC Facility PBX/PS911/Shared Tenant VoIP Provider | A | OK | 918-463-2921 |
| CCC | Citizens Communications Corporation | CLEC Facility | A | VA | 540-745-2111 |
| CCC3 | Cloud Computing Concepts LLC | VoIP Provider | A | USA - Nationwide | 877-247-4949 |
| CCCC | Coastal Carolina Community College - CANCELLED | VoIP Provider | C | NC | 910-455-1221 |
| CCCMD | Carroll Community College(Cancelled) | PBX/PS911/Shared Tenant | C | MD | 410-386-8060 |
| CCCOM | CC Communications | ILEC VoIP Reseller | A | NV | 775-315-5158 |
| CCG | Campus Communications Group Inc. | CLEC Facility VoIP Provider | A | FL | IL | TX | 888-799-7249 |
| CCG1 | Chesterfield County Government | PBX/PS911/Shared Tenant | VoIP | A | VA | 804-796-7127 |
| CCGBL | Connect Call Global - CANCELLED | VoIP Provider | C | USA | 855-348-1800 |
| CCGC | CCG Connect | VoIP Provider | A | USA - Nationwide | 513-438-5000 |
| CCGOV | Clinton County Government | PBX/PS911/Shared Tenant | A | NY | 518-561-3370 |
| CCH | Chester County Hospital (Cancelled) | PBX | C | PA | 610-431-5000 |
| CCHNL | City & County of Honolulu | VoIP Provider | A | HI | 808-768-4479 |
| CCI | Cat Communications International, Inc. (CANCELLED) | Facillity | C | MI | 540-444-2125 |
| CCINC | ClearCom Inc. - CANCELLED | CLEC Reseller VoIP Reseller | C | HI | 808-520-9003 |
| CCIT6 | County of Colusa | PBX/PS911/Shared Tenant | A | CA | 530-218-8223 |
| CCITX | Consolidated Communications of Texas Company LLC | CLEC Facility CLEC Reseller ILEC VoIP Provider | A | IL | TX | 916-746-3000 |
| CCMTC | Clear Creek Mutual Telephone Company | Co-Op/Rural | A | OR | 503-631-2101 |
| CCN | Community Care Network | | | | |
| CCN | Community Care Network | PBX/PS911/Shared Tenant | A | VT | 802-558-4800 |
| CCN01 | Clear Call Networks(Inactive) | PBX/PS911/Shared Tenant | C | IL | 312-446-0941 |
| CCOLL | Central College - CANCELLED | 9-1-1 Admin-CPE ALI (9-1-1 Jurisdiction/PSAP ONLY) | C | IA | 641-628-9000 |
| CCOMM | Cunningham Communications | CLEC Facility | A | KS | 785-545-3215 |